darktable preset inspired by KodakKodachrome 25

What the style changes

The style adds four darktable modules. It aims at what photographers say about Kodachrome 25: rich, warm reds, deep blacks, and an overall look more subtle than Kodachrome 64. The sources are detailed on the Kodak Kodachrome 25 film page. All figures below come from renders made with darktable-cli 5.6.0 at 1000 px, measured in CIELab.

• More contrast, a little less than the Kodachrome 64 style. Contrast rises from 14.3 to 16.6 on photo 0775, where the Kodachrome 64 style gives 16.9, and from 30.7 to 33.2 on photo 1014. The darkest 5 % of photo 1014 fall from L 2.6 to 0.8. Reviewers describe the 25 as more subtle than the 64.
• Dense reds. color equalizer raises red saturation and lowers its brightness, rgb primaries makes the red slightly purer, and oranges move a little toward red. The pink T-shirt gains chroma (33.7 to 41.6) and its hue moves from 358.8° to 5.1°.
• Warmth without tinting the shadows. The “film” color balance rgb instance adds warmth to the midtones and highlights and leaves the shadows neutral.
• Skies without cyan. The sky moves from 273.6° to 276.7° and gains little chroma (27.5 to 29.0). Simon Foale noticed a cyan tendency in the 64 and not in the 25, so this style does not shift blues toward cyan.
• No grain. With an RMS granularity of 9 on the datasheet, the style adds none.

For comparison, the t3mujinpack style for the same film, rendered on the same files, reaches a contrast of 17.9 on photo 0775 and lightens and desaturates the sky (chroma 21.8, against 27.5 for the base rendering). This style follows the written sources instead, which describe deep, natural color.

What it leaves alone

• Your base development. The style contains no exposure, no sigmoid or filmic, no white balance, no color calibration and no LUT: those stay as you set them.
• Your pipeline order. The style file carries no module order list, so it does not impose one on your image.
• Your own color balance rgb. The style’s instance is named “film”, so it is added next to yours without changing it (unless the photo already has an instance named “film”, for example from an earlier application of the style).

What it does not leave alone: applied from the lighttable or the darkroom, each module of the style replaces the instance of the same name on the photo, or is added if there is none. The style’s unnamed modules, rgb primaries, color equalizer and tone curve, therefore overwrite any settings you had already made in those modules. Your earlier settings stay in the history stack. Exporting with a style, or rendering with darktable-cli as our measurements do, adds the style’s modules as separate instances instead. Details in Install and apply darktable styles.

Limits

• An interpretation, not a calibration. No slide was scanned to tune the style.
• Few sources specific to the 25. Most descriptions of “Kodachrome” concern the 64 or the whole line. The difference between the 25 and the 64 rests mainly on two reviewers, Simon Foale and Fuji X Weekly.
• Contrast is nuanced. A brief for “high contrast” Kodachrome was toned down, because the sources describe the 25 as more subtle than the 64. The stronger reds come from generic descriptions of Kodachrome.
• Greens and skin. No source covers them for the 25, so the settings are cautious. Skin chroma still rises from 16.4 to 21.5 (+31 %), with the hue unchanged.
• Grain. The style assumes it is invisible at screen size and adds no grain. John Shaw saw it at 100 % on a scan.
• Scans differ. Online scans of Kodachrome vary with the scanner; this style is not matched to any of them.

Tips

• For more contrast, steepen the tone curve or raise the red saturation in color equalizer. The Kodachrome 64 style already goes further in that direction.
• Mind the skin. If skin looks too red, lower the saturation of red and orange in color equalizer.
• Installation: see Install and apply darktable styles.